fixed example to check if the session exists when getting flash messages to avoid starting sessions when not needed
added doctrine tags to reference
Documented 'Entities & Entity mapping' section
Documented "translation" section
Clearified controllers as services
the Filesystem component including a tagged API was added in Symfony 2.1
Merge pull request #2564 from fabpot/session

fixed example to check if the session exists when getting flash messages to avoid starting sessions when not needed
Merge pull request #2583 from pvolok/doctrine_tags

Added doctrine tags to the reference
Link to UserProviderInterface correction
Update target_path.rst

need this change for the 2.2.1 branch working
Merge pull request #2606 from xabbuh/issue2391

the Filesystem component including a tagged API was added in Symfony 2.1
Merge branch '2.0' into 2.1

Conflicts:
	reference/dic_tags.rst
added kernel.cache_clearer tag to the ref
Update database.rst

Changed to the correct value on assertEquals()
Merge pull request #2608 from pvolok/cache_clearer_tag

Added kernel.cache_clearer tag to the reference
Merge pull request #2610 from biruwon/2.1

Update database.rst
Corrects exception controller name
Improved code of custom authentication provider cookbook article
Book/Doctrine : Adding a line about the "--no-backup" option ...

... in the "Generating Getters and Setters" section
Changing quote to (double backticks)